/**
 * (C) Copyright IBM Corp. 2010, 2015
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 */

package com.ibm.bi.dml.runtime.functionobjects;

/**
 * Integer modulus, where we adhere to the defined R semantics:
 * 
 * ("%% indicates x mod y and %/% indicates integer division. 
 * It is guaranteed that x == (x %% y) + y * ( x %/% y ) (up to rounding error) 
 * unless y == 0")
 * 
 */
public class Modulus extends ValueFunction 
{

	private static final long serialVersionUID = -1409182981172200840L;

	private static Modulus singleObj = null;
	private IntegerDivide _intdiv = null;
	
	private Modulus() {
		_intdiv = IntegerDivide.getIntegerDivideFnObject();
	}
	
	public static Modulus getModulusFnObject() {
		if ( singleObj == null )
			singleObj = new Modulus();
		return singleObj;
	}
	
	public Object clone() throws CloneNotSupportedException {
		// cloning is not supported for singleton classes
		throw new CloneNotSupportedException();
	}

	@Override
	public double execute(double in1, double in2) {
		if( in2==0.0 || in2==-0.0 )
			return Double.NaN;
		return in1 - _intdiv.execute(in1, in2)*in2;
	}

	@Override
	public double execute(double in1, long in2) {
		if( in2==0 )
			return Double.NaN;
		return in1 - _intdiv.execute(in1, in2)*in2;
	}

	@Override
	public double execute(long in1, double in2) {
		if( in2==0.0 || in2==-0.0 )
			return Double.NaN;
		return in1 - _intdiv.execute(in1, in2)*in2;
	}

	@Override
	public double execute(long in1, long in2) {
		if( in2==0 )
			return Double.NaN;
		return in1 - _intdiv.execute(in1, in2)*in2;
	}	
	
}
